BACKGROUND Alkaline tide is the transient increase in blood and urine pH following stimulation of gastric acid secretion. It is attributed to HCO3- release from parietal cells in parallel with H+ secretion. The enzyme carbonic anhydrase is thought to be responsible for HCO3- production from CO2 and OH- in the parietal cell. OBJECTIVE To examine the effect of pretreatment with the carbonic anh...

A partially purified bovine cortical bone acid phosphatase, which shared similar characteristics with a class of acid phosphatase known as tartrate-resistant acid phosphatase, was found to dephosphorylate phosphotyrosine and phosphotyrosyl proteins, with little activity toward other phosphoamino acids or phosphoseryl histones. The pH optimum was about 5.5 with p-nitrophenyl phosphate as substra...

Hydrogen sulfide (H2S) is a very common odor nuisance which is best controlled by chemical or biological scrubbing. Under alkaline pH, the amount of H2S that can be solubilized in a scrubbing liquid increases significantly, and therefore, gas-liquid mass transfer limitations can be reduced. To date, biological scrubbing of H2S has been limited to neutral or acidic pH, despite the potential bene...

Studies with partially purified extracts of the nicotinamide adenine dinucleotide-linked l(+)-lactate dehydrogenase of Streptococcus cremoris US3 showed that fructose-1,6-diphosphate (FDP) was essential for the catalytic reduction of pyruvate in the pH range 5.0 to 7.0, outside of which the organism does not grow. In the absence of FDP, enzyme activity was observed only in the region of pH 8.0....

A novel pH-regulated locus inducible over 100-fold in alkaline media was identified in Escherichia coli through screening of 93,000 Mu dI1734 (lacZ Kmr) operon fusions at pH 6.5 and pH 8.5. Four lacZ fusions that showed expression only at the higher pH were mapped at 67.5 min by P1 transduction crosses. The locus was designated alx.

Photosynthetic carbon uptake of the tropical seagrass Thalassia hemprichii (Ehrenb.) Aschers was studied by several methods. Photosynthesis in buffered seawater in media in the range of pH 6 to pH 9 showed an exponentially increasing rate with decreasing pH, thus indicating that free CO(2) was a photosynthetic substrate. However, these experiments were unable to determine whether photosynthesis...

Ammonium stripping has gained increasing interest for nitrogen recovery in anaerobically digested effluents. However, the stripped effluents often still do not meet discharge standards, having high pH and residual pollutants. Constructed wetlands (CWs) are an easy to operate ecosystem and have a long history of application in treatment of wastewaters with extreme pH, such as acid mine drainage....

The preparation of a new stable and active form of chymotrypsin is described. The enzyme possesses threonine-147 instead of alanineas the NH&erminal group of the C chain and has been called ai-chymotrypsin. The conformational transition that affects chymotrypsins at alkaline pH was investigated and compared with that of 01and &chymotrypsins by studying the kinetic constants and their pH depende...